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High-Performance Alkaline Seawater Electrolysis with Anomalous Chloride Promoted Oxygen Evolution Reaction |
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| Authors: | Hao Liu Wei Shen Dr Huanyu Jin Jun Xu Prof Pinxian Xi Prof Juncai Dong Prof Yao Zheng Prof Shi-Zhang Qiao |
| Institution: | 1. School of Chemical Engineering and Advanced Materials, The University of Adelaide, 5005 Adelaide, SA, Australia
These authors contributed equally to this work.;2. College of Chemistry and Chemical Engineering, Lanzhou University, 730000 Lanzhou, China These authors contributed equally to this work.;3. School of Chemical Engineering and Advanced Materials, The University of Adelaide, 5005 Adelaide, SA, Australia;4. College of Chemistry and Chemical Engineering, Lanzhou University, 730000 Lanzhou, China;5. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China |
| Abstract: | A highly selective and durable oxygen evolution reaction (OER) electrocatalyst is the bottleneck for direct seawater splitting because of side reactions primarily caused by chloride ions (Cl−). Most studies about OER catalysts in seawater focus on the repulsion of the Cl− to reduce its negative effects. Herein, we demonstrate that the absorption of Cl− on the specific site of a popular OER electrocatalyst, nickel-iron layered double hydroxide (NiFe LDH), does not have a significant negative impact; rather, it is beneficial for its activity and stability enhancement in natural seawater. A set of in situ characterization techniques reveals that the adsorption of Cl− on the desired Fe site suppresses Fe leaching, and creates more OER-active Ni sites, improving the catalyst's long-term stability and activity simultaneously. Therefore, we achieve direct alkaline seawater electrolysis for the very first time on a commercial-scale alkaline electrolyser (AE, 120 cm2 electrode area) using the NiFe LDH anode. The new alkaline seawater electrolyser exhibits a reduction in electricity consumption by 20.7 % compared to the alkaline purified water-based AE using commercial Ni catalyst, achieving excellent durability for 100 h at 200 mA cm−2. |
| Keywords: | Alkaline Water Electrolyser Chloride Adsorption NiFe LDH Oxygen Evolution Reaction Seawater Electrolysis |